Bug 155092

Summary:	js/arraybuffer-wrappers.html is a flaky time out
Product:	WebKit	Reporter:	Alexey Proskuryakov <ap>
Component:	JavaScriptCore	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	fpizlo, ggaren, jlewis3, keith_miller, ryanhaddad, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Alexey Proskuryakov 2016-03-06 10:01:03 PST

js/arraybuffer-wrappers.html is a new test that times out very frequently (and when it doesn't, it runs fast).

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=js%2Farraybuffer-wrappers.html

Comment 1 Keith Miller 2016-03-06 21:30:19 PST

Is the test still flakey? The link appears to be dead and the test doesn't show up on https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html

Comment 2 Keith Miller 2016-03-06 21:33:47 PST

Wait, nevermind. My internet was acting up and the page was not loading properly.

Comment 3 Ryan Haddad 2016-03-07 11:40:27 PST

Marked test as flaky in <http://trac.webkit.org/projects/webkit/changeset/197696>

Comment 4 Alexey Proskuryakov 2016-03-10 22:25:50 PST

Keith, does this look more like a test bug, or a JSC bug?

Comment 5 Keith Miller 2016-03-10 23:35:56 PST

(In reply to comment #4)
> Keith, does this look more like a test bug, or a JSC bug?

This looks like a JSC bug. I would expect this test to finish in < 20ms and it definitely should not take more than 1s.

Comment 6 Radar WebKit Bug Importer 2016-03-12 17:28:46 PST

<rdar://problem/25130361>

Comment 7 Alexey Proskuryakov 2017-08-25 09:51:42 PDT

*** Bug 155043 has been marked as a duplicate of this bug. ***

Comment 8 Alexey Proskuryakov 2017-08-25 09:55:13 PDT

Still happening very frequently (also on iOS and Gtk, where we don't have the expectation yet).

Keith, would you mind taking a look?

Comment 9 Matt Lewis 2017-09-06 11:28:05 PDT

Marked this test as flaky on iOS for now:
https://trac.webkit.org/changeset/221687/webkit

Comment 10 Keith Miller 2017-09-06 11:39:01 PDT

(In reply to Alexey Proskuryakov from comment #8)
> Still happening very frequently (also on iOS and Gtk, where we don't have
> the expectation yet).
> 
> Keith, would you mind taking a look?

Oh, I looked into this a bit. It seems like it's some kind of GC deadlock based on the spindumps on the bots. I'm not sure what causes it or how to reproduce it. I tried running the test (and the 10 tests leading up to it) on all the cores on my machine repeatedly but the issue never reproduced.

Comment 11 Alexey Proskuryakov 2017-09-07 09:26:15 PDT

Is there any instrumentation that can be added to get more information when this happens on the bots?

Comment 12 Keith Miller 2017-09-07 11:11:39 PDT

(In reply to Alexey Proskuryakov from comment #11)
> Is there any instrumentation that can be added to get more information when
> this happens on the bots?

I can't think of anything off the top of my head but maybe @pizlo has some ideas. It's also possible that this isn't a GC deadlock but that's just my current hypothesis.